path: root/gs/lib/gs_setpd.ps

%    Copyright (C) 1994, 1996, 1997, 1998 Aladdin Enterprises.  All rights reserved.
% 
% This file is part of Aladdin Ghostscript.
% 
% Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
% or distributor accepts any responsibility for the consequences of using it,
% or for whether it serves any particular purpose or works at all, unless he
% or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
% License (the "License") for full details.
% 
% Every copy of Aladdin Ghostscript must include a copy of the License,
% normally in a plain ASCII text file named PUBLIC.  The License grants you
% the right to copy, modify and redistribute Aladdin Ghostscript, but only
% under certain conditions described in the License.  Among other things, the
% License requires that the copyright notice and this notice be preserved on
% all copies.

% 
% The current implementation of setpagedevice has the following limitations:
%	- It doesn't attempt to "interact with the user" for Policy = 2.

languagelevel 1 .setlanguagelevel
level2dict begin

% ---------------- Redefinitions ---------------- %

% Redefine .beginpage and .endpage so that they call BeginPage and
% EndPage respectively if appropriate.

% We have to guard against the BeginPage procedure not popping its operand.
% This is really stupid, but the Genoa CET does it.
/.beginpage {		% - .beginpage -
  .currentshowpagecount {
    .currentpagedevice pop
    dup null ne { /BeginPage .knownget } { pop false } ifelse {
		% Stack: ... pagecount proc
       count 2 .execn
		% Stack: ... ..???.. oldcount
       count 1 add exch sub { pop } repeat
    } {
      pop
    } ifelse
  } if
} bind odef

% Guard similarly against EndPage not popping its operand.
/.endpage {		% <reason> .endpage <print_bool>
  .currentshowpagecount {
    1 index .currentpagedevice pop
    dup null ne { /EndPage .knownget } { pop false } ifelse {
		% Stack: ... reason pagecount reason proc
      count 2 .execn
		% Stack: ... ..???.. print oldcount
      count 2 add exch sub { exch pop } repeat
    } {
      pop pop 2 ne
    } ifelse
  } {
    2 ne
  } ifelse
} bind odef

% Define interpreter callouts for handling gstate-saving operators,
% to make sure that they create a page device dictionary for use by
% the corresponding gstate-restoring operator.
% We'd really like to avoid the cost of doing this, but we don't see how.
% The names %gsavepagedevice, %savepagedevice, %gstatepagedevice,
% %copygstatepagedevice, and %currentgstatepagedevice are known to the
% interpreter.

(%gsavepagedevice) cvn
 { currentpagedevice pop gsave
 } bind def

(%savepagedevice) cvn
 { currentpagedevice pop save
 } bind def

(%gstatepagedevice) cvn
 { currentpagedevice pop gstate
 } bind def

(%copygstatepagedevice) cvn
 { currentpagedevice pop copy
 } bind def

(%currentgstatepagedevice) cvn
 { currentpagedevice pop currentgstate
 } bind def

% Define interpreter callouts for handling gstate-restoring operators
% when the current page device needs to be changed.
% The names %grestorepagedevice, %grestoreallpagedevice,
% %restorepagedevice, and %setgstatepagedevice are known to the interpreter.

/.installpagedevice
 {	% Since setpagedevice doesn't create new device objects,
	% we must (carefully) reinstall the old parameters in
	% the same device.
   .currentpagedevice pop null currentdevice null .trysetparams
   dup type /booleantype eq
    { pop pop }
    {		% This should never happen!
      DEBUG { (Error in .trysetparams!\n) print pstack flush } if
      cleartomark pop pop pop
      /.installpagedevice cvx /rangecheck signalerror
    }
   ifelse pop pop
	% A careful reading of the Red Book reveals that an erasepage
	% should occur, but *not* an initgraphics.
   erasepage .beginpage
 } bind def

/.uninstallpagedevice
 { 2 .endpage { .currentnumcopies false .outputpage } if
   nulldevice
 } bind def

(%grestorepagedevice) cvn
 { .uninstallpagedevice grestore .installpagedevice
 } bind def

(%grestoreallpagedevice) cvn
 { .uninstallpagedevice grestore .installpagedevice grestoreall
 } bind def

(%restorepagedevice) cvn
 { .uninstallpagedevice grestore .installpagedevice restore
 } bind def

(%setgstatepagedevice) cvn
 { .uninstallpagedevice setgstate .installpagedevice
 } bind def

% Redefine .currentnumcopies so it consults the NumCopies device parameter.
/.numcopiesdict mark
  /NumCopies dup
.dicttomark readonly def

/.currentnumcopies
 { currentdevice //.numcopiesdict .getdeviceparams
   dup type /integertype eq
    { exch pop exch pop }
    { cleartomark #copies }
   ifelse
 } bind odef

% Redefine .currentpagedevice and .setpagedevice so they convert between
% null and a fixed empty directionary.
/.nullpagedevice 0 dict readonly def
/.currentpagedevice {
  //.currentpagedevice exch dup null eq { pop //.nullpagedevice } if exch
} bind odef
/.setpagedevice {
  dup //.nullpagedevice eq { pop null } if //.setpagedevice
} bind odef

% ---------------- Auxiliary definitions ---------------- %

% Define the required attributes of all page devices, and their default values.
% We don't include attributes such as .MediaSize, which all devices
% are guaranteed to supply on their own.
/.defaultpolicies mark
  /PolicyNotFound 1
  /PageSize 0
  /PolicyReport {pop} bind
.dicttomark readonly def
/.requiredattrs mark
  /PageOffset [0 0] readonly
% We define InputAttributes and OutputAttributes with a single
% dummy media type that handles pages of any size.
% Devices that care will override this.
  /InputAttributes mark 0
	% Since sizes match within 5 user units, we need to set the smallest
	% PageSize to 6 units so that [0 0] will fail.
    mark /PageSize [6 dup 16#7ffff dup] .dicttomark readonly
  .dicttomark readonly
  (%MediaSource) 0
  /OutputAttributes mark 0
    mark .dicttomark readonly
  .dicttomark readonly
  (%MediaDestination) 0
  /Install {.callinstall} bind
  /BeginPage {.callbeginpage} bind
  /EndPage {.callendpage} bind
  /Policies .defaultpolicies
.dicttomark readonly def

% Define currentpagedevice so it creates the dictionary on demand if needed,
% adding all the required entries defined just above.
% We have to deal specially with entries that the driver may change
% on its own.
/.dynamicppkeys mark
  /.MediaSize dup		% because it changes when PageSize is set
  /PageCount dup
.dicttomark readonly def
/.makecurrentpagedevice		% - .makecurrentpagedevice <dict>
 { currentdevice null .getdeviceparams
	% In case of duplicate keys, .dicttomark takes the entry
	% lower on the stack, so we can just append the defaults here.
   .requiredattrs { } forall .dicttomark
   dup .setpagedevice
 } bind def
/currentpagedevice
 { .currentpagedevice
    { dup length 0 eq
       { pop .makecurrentpagedevice
       }
       {	% If any of the dynamic keys have changed,
		% we must update the page device dictionary.
	 currentdevice //.dynamicppkeys .getdeviceparams .dicttomark
	  {	% Stack: current key value
	    2 index 2 index .knownget { 1 index ne } { true } ifelse
	     { 2 index wcheck not
		{	% This is the first entry being updated.
			% Copy the dictionary to make it writable.
		  3 -1 roll dup length dict .copydict
		  3 1 roll
		}
	       if
	       2 index 3 1 roll put
	     }
	     { pop pop
	     }
	    ifelse
	  }
	 forall
		% We would like to do a .setpagedevice so we don't keep
		% re-creating the dictionary.  Unfortunately, the effect
		% of this is that if any dynamic key changes (PageCount
		% in particular), we will do the equivalent of a
		% setpagedevice at the next restore or grestore.
		% Therefore, we make the dictionary read-only, but
		% we don't store it away.  I.e., NOT:
		% dup wcheck { .setpagedevice .currentpagedevice pop } if
	 readonly
       }
      ifelse
    }
   if
 } bind odef

% The implementation of setpagedevice is quite complex.  Currently,
% everything but the media matching algorithm is implemented here.

% By default, we only present the requested changes to the device,
% but there are some parameters that require special merging action.
% Define those parameters here, with the procedures that do the merging.
% The procedures are called as follows:
%	<merged> <key> <new_value> -proc- <merged> <key> <new_value'>
/.mergespecial mark
  /InputAttributes
   { dup null eq
      { pop null
      }
      { 3 copy pop .knownget
	 { dup null eq
	    { pop dup length dict }
	    { dup length 2 index length add dict .copydict }
	   ifelse
	 }
	 { dup length dict
	 }
        ifelse .copydict readonly
      }
     ifelse
   } bind
  /OutputAttributes 1 index
  /Policies
    { 3 copy pop .knownget
       { dup length 2 index length add dict .copydict }
       { dup length dict }
      ifelse copy readonly
    } bind
.dicttomark readonly def

% Define the keys used in input attribute matching.
/.inputattrkeys [
  /PageSize /MediaColor /MediaWeight /MediaType /InsertSheet
	% The following are documented in Adobe's supplement for v2017.
  /LeadingEdge /MediaClass
] readonly def
% Define other keys used in media selection.
/.inputselectionkeys [
  /MediaPosition /Orientation
] readonly def

% Define the keys used in output attribute matching.
/.outputattrkeys [
  /OutputType
] readonly def

% Define all the parameters that should always be copied to the merged
% dictionary.
/.copiedkeys [
  /OutputDevice
  .mergespecial { pop } forall
  .inputattrkeys aload pop
  .inputselectionkeys aload pop
  .outputattrkeys aload pop
] readonly def

% Define the parameters that should not be presented to the device.
% The procedures are called as follows:
%	<merged> <key> <value> -proc-
% The procedure leaves all its operands on the stack and returns
% true iff the key/value pair should be presented to .putdeviceparams.
/.presentspecial mark
  .dynamicppkeys { pop false } forall
			% We must ignore an explicit request for .MediaSize,
			% because media matching always handles this.
  /.MediaSize false
  /Name false
  /OutputDevice false
  /PageOffset false
  /PageSize false		% obsolete alias for .MediaSize
  /InputAttributes false
  .inputattrkeys
    { dup /PageSize eq
       { pop }
       { { 2 index /InputAttributes .knownget { null eq } { true } ifelse } }
      ifelse
    }
  forall
  .inputselectionkeys { false } forall
  /OutputAttributes false
  .outputattrkeys
    { { 2 index /OutputAttributes .knownget { null eq } { true } ifelse } }
  forall
  /Install false
  /BeginPage false
  /EndPage false
  /Policies false
	% Our extensions:
  /HWColorMap
    {			% HACK: don't transmit the color map, because
			% window systems can change the color map on their own
			% incrementally.  Someday we'll have a better
			% solution for this....
      false
    }
  /ViewerPreProcess false
.dicttomark readonly def

% Define access to device defaults.
/.defaultdeviceparams
 { finddevice null .getdeviceparams
 } bind def

% Select media (input or output).  The hard work is done in an operator:
%	<pagedict> <attrdict> <policydict> <keys> .matchmedia <key> true
%	<pagedict> <attrdict> <policydict> <keys> .matchmedia false
%	<pagedict> null <policydict> <keys> .matchmedia null true
/.selectmedia		% <orig> <request> <merged> <failed>     <-- retained
			%   <attrdict> <policydict> <attrkeys> <mediakey>
			%   .selectmedia
 { 5 index 5 -2 roll 4 index .matchmedia
		% Stack: orig request merged failed attrkeys mediakey
		%   (key true | false)
    { 4 index 3 1 roll put pop
    }
    {	% Adobe's implementations have a "big hairy heuristic"
	% to choose the set of keys to report as having failed the match.
	% For the moment, we report any keys that are in the request
	% and don't have the same value as in the original dictionary.
      5 index 1 index .knownget
       { 4 index 3 1 roll put }
       { 3 index exch .undef }
      ifelse
       {	% Stack: <orig> <request> <merged> <failed> <attrkey>
	 3 index 1 index .knownget
	  { 5 index 2 index .knownget { ne } { pop true } ifelse }
	  { true }
	 ifelse		% Stack: ... <failed> <attrkey> <report>
	  { 2 copy /rangecheck put }
	 if pop
       }
      forall
    }
   ifelse
 } bind def

% Apply Policies to any unprocessed failed requests.
% As we process each request entry, we replace the error name
% in the <failed> dictionary with the policy value,
% and we replace the key in the <merged> dictionary with its prior value
% (or remove it if it had no prior value).
/.policyprocs mark
% These procedures are called with the following on the stack:
%   <orig> <merged> <failed> <Policies> <key> <policy>
% They are expected to consume the top 2 operands.
% NOTE: we currently treat all values other than 0, 1, or 7 (for PageSize)
% the same as 0, i.e., we signal an error.
  0 {		% Set errorinfo and signal a configurationerror.
	pop dup 4 index exch get 2 array astore
	$error /errorinfo 3 -1 roll put
	cleartomark
	/setpagedevice load /configurationerror signalerror
  } bind
  1 {		% Roll back the failed request to its previous status.
DEBUG { (Rolling back.\n) print pstack flush } if
	3 index 2 index 3 -1 roll put
	4 index 1 index .knownget
	 { 4 index 3 1 roll put }
	 { 3 index exch .undef }
	ifelse
  } bind
  7 {		% For PageSize only, just impose the request.
	1 index /PageSize eq
	 { pop pop 1 index /PageSize 7 put }
	 { .policyprocs 0 get exec }
	ifelse
  } bind
.dicttomark readonly def
/.applypolicies		% <orig> <merged> <failed> .applypolicies
			%   <orig> <merged'> <failed'>
 { 1 index /Policies get 1 index
    { type /integertype eq
       { pop		% already processed
       }
       { 2 copy .knownget not { 1 index /PolicyNotFound get } if
			% Stack: <orig> <merged> <failed> <Policies> <key>
			%   <policy>
	 .policyprocs 1 index .knownget not { .policyprocs 0 get } if exec
       }
      ifelse
    }
   forall pop
 } bind def

% Prepare to present parameters to the device, by spreading them onto the
% operand stack and removing any that shouldn't be presented.
/.prepareparams		% <params> .prepareparams -mark- <key1> <value1> ...
 { mark exch dup
    {			% Stack: -mark- key1 value1 ... merged key value
      .presentspecial 2 index .knownget
       { exec { 3 -1 roll } { pop pop } ifelse }
       { 3 -1 roll }
      ifelse
    }
   forall pop
 } bind def

% Put device parameters without resetting currentpagedevice.
% (.putdeviceparams clears the current page device.)
/.putdeviceparamsonly	% <device> <Policies|null> <require_all> -mark-
			%   <key1> <value1> ... .putdeviceparamsonly
			% On success: <device> <eraseflag>
			% On failure: <device> <Policies|null> <req_all> -mark-
			%   <key1> <error1> ...
 { .currentpagedevice
    { counttomark 4 add 1 roll .putdeviceparams
      dup type /booleantype eq { 3 } { counttomark 5 add } ifelse -1 roll
      .setpagedevice
    }
    { pop .putdeviceparams
    }
   ifelse
 } bind def

% Try setting the device parameters from the merged request.
/.trysetparams		% <merged> <(ignored)> <device> <Policies>
			%   .trysetparams
 { true 4 index .prepareparams
			% Add the computed .MediaSize.
			% Stack: merged (ignored) device Policies -true-
			%   -mark- key1 value1 ...
   counttomark 5 add index .computemediasize
   exch pop exch pop /.MediaSize exch
DEBUG { (Putting.\n) print pstack flush } if
   .putdeviceparamsonly
DEBUG { (Result of putting.\n) print pstack flush } if
 } bind def

% Compute the media size and initial matrix from a merged request (after
% media selection).
/.computemediasize	% <request> .computemediasize
			%   <request> <matrix> <[width height]>
 { dup /PageSize get					% requested page size
   1 index /InputAttributes get
     2 index (%MediaSource) get get /PageSize get	% media size
							% (may be a range)
   2 index /Policies get
     dup /PageSize .knownget
      { exch pop } { /PolicyNotFound get } ifelse	% PageSize policy,
							% affects scaling
   3 index /Orientation .knownget not { null } if
   4 index /RollFedMedia .knownget not { false } if
   matrix .matchpagesize not {
		% This is a "can't happen" condition!
     /setpagedevice load /rangecheck signalerror
   } if
   2 array astore
 } bind def

% ---------------- setpagedevice itself ---------------- %

/setpagedevice
 {		% We mustn't pop the argument until the very end,
		% so that the pseudo-operator machinery can restore the stack
		% if an error occurs.
   mark 1 index currentpagedevice

		% Check whether we are changing OutputDevice;
		% also handle the case where the current device
		% is not a page device.
		% Stack: mark <request> <current>
DEBUG { (Checking.\n) print pstack flush } if

   dup /OutputDevice .knownget
    {		% Current device is a page device.
      2 index /OutputDevice .knownget
       {	% A specific OutputDevice was requested.
	 2 copy eq
	  { pop pop null }
	  { exch pop }
	 ifelse
       }
       { pop null
       }
      ifelse
    }
    {		% Current device is not a page device.
		% Use the default device.
      1 index /OutputDevice .knownget not { .defaultdevicename } if
    }
   ifelse
   dup null eq
    { pop
    }
    { exch pop .defaultdeviceparams
		% In case of duplicate keys, .dicttomark takes the entry
		% lower on the stack, so we can just append the defaults here.
      .requiredattrs { } forall .dicttomark
    }
   ifelse

		% Check whether a viewer wants to intervene.
		% We must check both the request (which takes precedence)
		% and the current dictionary.
		% Stack: mark <request> <orig>
   exch dup /ViewerPreProcess .knownget
    { exec }
    { 1 index /ViewerPreProcess .knownget { exec } if }
   ifelse exch

		% Construct a merged request from the actual request plus
		% any keys that should always be propagated.
		% Stack: mark <request> <orig>
DEBUG { (Merging.\n) print pstack flush } if

   exch 1 index length 1 index length add dict
   .copiedkeys
    {		% Stack: <orig> <request> <merged> <key>
      3 index 1 index .knownget { 3 copy put pop } if pop
    }
   forall
		% Stack: <orig> <request> <merged>
   dup 2 index
    {		% stack: <orig> <request> <merged> <merged> <rkey> <rvalue>
      .mergespecial 2 index .knownget { exec } if
      put dup
    }
   forall pop
		% Hack: if FIXEDRESOLUTION is true, discard any attempt to
		% change HWResolution.
   FIXEDRESOLUTION { dup /HWResolution .undef } if
		% Hack: if FIXEDMEDIA is true, discard any attempt to change
		% PageSize or HWSize.
   FIXEDMEDIA
    { dup /PageSize 4 index /PageSize get put
      dup /HWSize 4 index /HWSize get put
    } if

		% Select input and output media.
		% Stack: mark <orig> <request> <merged>
DEBUG { (Selecting.\n) print pstack flush } if

   0 dict	% <failed>
   1 index /InputAttributes .knownget
    { 2 index /Policies get
      .inputattrkeys (%MediaSource) cvn .selectmedia
    } if
   1 index /OutputAttributes .knownget
    { 2 index /Policies get
      .outputattrkeys (%MediaDestination) cvn .selectmedia
     } if
   3 -1 roll 4 1 roll		% temporarily swap orig & request
   .applypolicies
   3 -1 roll 4 1 roll		% swap back

		% Construct the new device, and attempt to set its attributes.
		% Stack: mark <orig> <request> <merged> <failed>
DEBUG { (Constructing.\n) print pstack flush } if

   currentdevice .devicename 2 index /OutputDevice get eq
    { currentdevice }
    { 1 index /OutputDevice get finddevice }
   ifelse
		%**************** We should copy the device here,
		%**************** but since we can't close the old device,
		%**************** we don't.  This is WRONG.
	%****************copydevice
   2 index /Policies get
   .trysetparams
   dup type /booleantype ne
    {		% The request failed.
		% Stack: ... <orig> <request> <merged> <failed> <device>
		%   <Policies> true mark <name> <errorname> ...
DEBUG { (Recovering.\n) print pstack flush } if
      counttomark 4 add index
      counttomark 2 idiv { dup 4 -2 roll put } repeat
      pop pop pop
		% Stack: mark ... <orig> <request> <merged> <failed> <device>
		%   <Policies>
      6 2 roll 3 -1 roll 4 1 roll
      .applypolicies
      3 -1 roll 4 1 roll 6 -2 roll
      .trysetparams		% shouldn't fail!
      dup type /booleantype ne
       { 2 { counttomark 1 add 1 roll cleartomark } repeat
         /setpagedevice load exch signalerror
       }
      if
    }
   if

		% The attempt succeeded.  Install the new device.
		% Stack: mark ... <merged> <failed> <device> <eraseflag>
DEBUG { (Installing.\n) print pstack flush } if

   pop 2 .endpage
    { 1 true .outputpage
      (>>setpagedevice, press <return> to continue<<\n) .confirm
    }
   if
		% .setdevice clears the current page device!
   .currentpagedevice pop exch
   .setdevice pop
   .setpagedevice

		% Merge the request into the current page device.
		% Stack: mark ... <merged> <failed>
   exch currentpagedevice dup length 2 index length add dict
   .copydict .copydict
		% Initialize the default matrix, taking media matching
		% into account.
   .computemediasize pop initmatrix concat
   dup /PageOffset .knownget
    {		% Translate by the given number of 1/72" units in device X/Y.
      dup 0 get exch 1 get
      2 index /HWResolution get dup 1 get exch 0 get
      4 -1 roll mul 72 div   3 1 roll mul 72 div
      idtransform translate
    }
   if
		% We must install the new page device dictionary
		% before calling the Install procedure.
   dup .setpagedevice
   .setdefaultscreen	% Set the default screen before calling Install.
   dup /Install .knownget { exec } if
   matrix currentmatrix .setdefaultmatrix
		% Erase and initialize the page.
   erasepage initgraphics
   .beginpage

		% Clean up, calling PolicyReport if needed.
		% Stack: mark ... <failed> <merged>
DEBUG { (Finishing.\n) print pstack flush } if

   exch dup length 0 ne
    { 1 index /Policies get /PolicyReport get
      counttomark 1 add 2 roll cleartomark
      exec
    }
    { cleartomark
    }
   ifelse pop

 } odef

end				% level2dict
.setlanguagelevel